The reduction of spectroscopic and chemical properties of an unknown biomolecule to their structural implications forms the basis of an important approach to structure elucidation. In the non-computer assisted process it is generally only in the later stages of the problem, after considerable expenditure of time and effort, that all structures consistent with the evidence can be drawn and examined by the chemist, because only then is the number of valid possibilities at a manageable level. Clearly, structure determination would be measurably expedited if the procesess of reducing the number of structures to that manageable level could be based exclusively on spectroscopic properties and executed by the computer. The proposed research is directed toward that end. Programs for the automated extraction of selected structural information from 13C-nmr, proton nmr, electronic absorption and mass spectra will be added to the infrared interpretative capabilities of the CASE (Computer-Assisted Structure Elucidation) network of programs. The substructure information generated by the spectrum interpreters serves as input for a molecule assembler (ASSEMBLE) which constructs all structural isomers compatible with it. The scope and efficiency of ASSEMBLE will be expanded to accommodate the additional spectroscopic methods. Spectrum simulation programs for 13C-nmr, electronic absorption and mass spectra will also be added to retrospectively rank the list of assembled molecules on the basis of the fit between predicted and observed spectroscopic properties.